Two days in advance.,Pat the lamb dry with paper towels.,Mash the anchovies with two tablespoons olive oil and the oil from their cans into a paste and spread the mixture over the lamb.,Cut the garlic into slivers.,Make small incisions under the skin of the lamb and insert slivers of garlic into them.,Sprinkle the lamb with pepper, wrap in foil and refrigerate.,A day in advance.,Preheat oven to 400 degrees.,Roast the bones for 30 minutes or until browned.,Add the vegetables and cook for a further 30 minutes.,Put the bones and the vegetables in a large stock pot and add two quarts water, the parsley, wine, tomatoes and bay leaf.,Simmer, uncovered, for two hours.,______,The following day, skim off the fat from the stock and discard.,Boil the stock down to one cup.,Set aside.,On the day of the dinner.,Preheat oven to 375 degrees.,Place the shallots and two tablespoons of olive oil in the bottom of a large roasting pan.,Place the lamb on a rack on top.,Roast for about 15 minutes a pound depending on how well done you like it (it is usually best served pink), about two-and-a-half hours altogether.,Heat the sauce in a small saucepan.,When the lamb is cooked, remove to a heated platter.,Remove the shallots with tongs and place them around the lamb.,Decorate with sprigs of rosemary.,Pour off the fat from the roasting juices.,Add the cooking juices to the sauce.,Bring to boil, correct seasoning and serve separately in a sauce boat.